A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Evaluate the reliability of online sources
Finding useful sources
Part I. Research and writing: from planning to production

Evaluate online sources as you do those in print, but more cautiously. The number of reliable Web sources grows every day, but they are still islands in a swamp of misinformation. If you find data available only on the Web, look for sites or online publications with these signs of reliability:

1. The site is sponsored by a reputable organization. Some sites supported by individuals are reliable; most are not.

2. It is related to a reliable professional journal.

3. It supplements reliable print sources. Some journals use the Web to host discussions among authors and readers, to offer data too new to be in libraries, to archive data not in articles, or to present illustrations too expensive to print. Many government and academic databases are only online.

4. It avoids heated advocacy for or against a contested social issue.

5. It does not make wild claims, attack other researchers, use abusive language, or make errors of spelling, punctuation, and grammar.

6. It indicates when the site was last updated. If it has no date, be cautious.

Trust a site only if careful readers would trust those who maintain it. If you don't know who maintains it, be skeptical.

Online services now provide reliable editions of many older texts. You'll also find well-edited texts at many university sites. It's “one-stop shopping”; you never have to move from your chair. Online services are, however, far less complete than most university libraries, and using them will teach you nothing about doing research in a real library. Some day, everything ever printed will be available online (a future that gives some researchers mixed feelings). But until then, surfing the Web doesn't replace prowling the stacks.